import {Vector4} from '../../build/three.module.js'
import {NURBSUtils} from '../curves/NURBSUtils.js'

/**
 * NURBS surface object
 *
 * Implementation is based on (x, y [, z=0 [, w=1]]) control points with w=weight.
 **/

var NURBSSurface = function (degree1, degree2, knots1, knots2 /* arrays of reals */, controlPoints /* array^2 of Vector(2|3|4) */) {
  this.degree1 = degree1
  this.degree2 = degree2
  this.knots1 = knots1
  this.knots2 = knots2
  this.controlPoints = []

  var len1 = knots1.length - degree1 - 1
  var len2 = knots2.length - degree2 - 1

  // ensure Vector4 for control points
  for (var i = 0; i < len1; ++i) {
    this.controlPoints[i] = []
    for (var j = 0; j < len2; ++j) {
      var point = controlPoints[i][j]
      this.controlPoints[i][j] = new Vector4(point.x, point.y, point.z, point.w)
    }
  }
}

NURBSSurface.prototype = {
  constructor: NURBSSurface,

  getPoint: function (t1, t2, target) {
    var u = this.knots1[0] + t1 * (this.knots1[this.knots1.length - 1] - this.knots1[0]) // linear mapping t1->u
    var v = this.knots2[0] + t2 * (this.knots2[this.knots2.length - 1] - this.knots2[0]) // linear mapping t2->u

    NURBSUtils.calcSurfacePoint(this.degree1, this.degree2, this.knots1, this.knots2, this.controlPoints, u, v, target)
  },
}

export {NURBSSurface}
